How Microwave-Assisted Extraction Works

Extracting compounds from various samples using traditional methods involves some give and take. You can choose to use Soxhlet, which is relatively inexpensive for equipment but uses a tremendous amount of solvent and takes hours to run.

Problem: Extracting compounds from various samples using traditional methods involves some give and take. You can choose to use Soxhlet, which is relatively inexpensive for equipment but uses a tremendous amount of solvent and takes hours to run. Sonication is fast, but it also requires copious amounts of solvent and banks of individual sonicators (which also adds to the cost) if your lab handles more than a few samples a day. Pressurized solvent extraction uses much less solvent, but only processes six samples per hour and the equipment is costly.

Solution: Microwave extraction has been used for many years to extract compounds from plastics, biological samples, foods, animal feeds, paper, wastewater and many other types of samples. In early 2008, the U.S. Environmental Protection Agency (USEPA) approved Method 3546 for microwave extraction of organic compounds from soils, sludges and sediments. It is a proven technique that is fast, uses significantly less solvent than traditional techniques and is cost-effective.

With the capability to process 40 samples simultaneously and a patented Xpress technology that provides optimum control for high-pressure extractions, the MARSXpress™ (CEM Corporation) microwave reaction system provides a fast, reliable platform for busy analytical laboratories, allowing 80 extractions and filtrations to be performed in less than four hours. The system uses 90 percent less solvent than Soxhlet, making it a much more environmentally friendly technique.

The advanced technology of the MARSXpress system makes it remarkably easy to use. The IR temperature sensors and the advanced design of the MARSXpress vessels allow the system to accurately measure the internal temperature of each vessel virtually instantaneously. The dual, NIST-traceable, calibrated temperature system provides unmatched control that you can rely on for the extraction results you need. First, the sample is weighed into a patented MARSXpress vessel and solvent is added. Microwave extraction is much more efficient than other methods, so you use significantly less solvent than with other techniques. The vessel is then capped and loaded into the carousel. The MARSXpress vessel features a simple screw-on cap and does not require the use of special tools. The carousel is then placed in the microwave, the appropriate method is loaded and the system is started. The MARSXpress comes with a pre-loaded library of USEPA-approved methods, though you can always program your own. Finally, the “start” button is pressed and your extractions are under way. It’s that simple. The SynergyPrep™ software displays and records temperature readings for all the vessels, so you will know for certain how well each sample performed. This is especially helpful when running samples from different sources on the same carousel.

Chemists in busy testing labs need accurate, dependable results in a timely manner. The MARSXpress system provides those results with a method that can help significantly reduce solvent usage and is also cost-effective.

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